Drinking in pregnancy could put children at an increased risk of developing depression as teenagers, according to new research.

The study, by the University of Bristol, used data from 14,541 pregnant mothers in the 1990s and is published in the journal Alcoholism: Clinical and Experimental Research.

Researchers analysed data from the mothers – 4,191 of whom had consumed alcohol between weeks 18 and 32 of pregnancy – and diagnoses of depression in their children at age 18.

Children whose mothers consumed alcohol at 18 weeks pregnant may have up to a 17% higher risk of depression at age 18 compared to those whose mothers did not drink, the study found.

The study also examined the drinking of the women’s partners, which is unlikely to have a direct biological effect on the developing fetus.

There was little evidence of any association between partner drinking and offspring depression in adolescence, suggesting the association seen with maternal drinking may be casual.

Dr Kayleigh Easey, senior research associate in genetic epidemiology, said: “It can be challenging to assess the causal effect of alcohol use in pregnancy and we have to be careful in the interpretation of results given the sensitivity of alcohol as a risk factor and traditional views around low-level drinking.

“Our study suggests that children whose mothers consumed alcohol at 18 weeks gestation have a higher risk of depression at age 18 compared to those who did not drink alcohol.

“What was really interesting here is that we also investigated paternal alcohol use during pregnancy and did not find a similar association.

“Many of the indirect factors that could explain the maternal effects are shared between mothers and partners (such as socio-demographic factors); despite this, we only found associations for mothers drinking.

“This study also illustrates the importance of considering partner behaviours as well as maternal behaviours – both to help identify causal relationship and because these may be important in their own right.”

The research used data from Bristol’s Children of the 90s, also known as the Avon Longitudinal Study of Parents and Children (ALSPAC), which has tracked pregnant mothers, their partners and children since the 1990s.

In January 2016, the Department of Health updated guidelines to advise pregnant women that the safest approach is to abstain from alcohol consumption during their entire pregnancy.